Isuzu 20LE - Engine Oil Consumption Excessive

6-12 ENGINE DIAGNOSIS (C22NE, 22LE, 20LE)
Engine Oil Consumption Excessive
Condition Possible cause Correction
Oil leaking Oil pan drain plug loose Retighten or replace gasket
Oil pan setting bolds loosened Retighten
Oil pan gasket broken Replace gasket
Front cover retaining bolts loose or
gasket broken
Retighten or replace gasket
Head cover retaining bolts loose
or gasket broken
Retighten or replace gasket
Oil filter adapter cracked Replace
Oil filter attaching bolt loose or
rubber gasket broken
Retighten or replace oil filter
Crankshaft front or rear oil seal
defective
Replace oil seal
Oil pressure unit loose or broken Retighten or replace
Blow-by gas hose broken Replace hose
Engine/Transmission coupling
area
Replace oil seal
Oil leaking into combustion
chambers due to poor seal in
valve system
Valve stem oil seal defective Replace
Valve stem or valve guide worn Replace valve and valve guide
Oil leaking into combustion
chambers due to poor seal in
cylinder parts
Cylinders and pistons worn
excessively
Rebore cylinder and replace
pistons and others
Piston ring gaps incorrectly
positioned
Correct
Piston rings set with wrong side up Correct
Piston rings sticking Rebore cylinder and replace
pistons and others
Piston ring and ring groove worn Replace pistons and others
Return ports in oil rings clogged Clean piston and replace rings
Crank case ventilation, Positive
Crankcase Ventilation System
malfunctioning
Positive Crankcase Ventilation
Hose clogged
Clean
Others Improper oil viscosity Use oil of recommended S.A.E.
viscosity
Continuous high speed driving and
or severe usage such as trailer
towing
Continuous high speed operation
and or severe usage will normally
cause increased oil consumption